1. Field of the Invention
Manufacture of cast resin lenses with particular reference to improvements in post-cure procedures.
2. Discussion of the Prior Art
In the manufacture of lenses of cast allyl diglycol carbonate and copolymers of the monomer and other resins, it is desirable to remove the castings early in the cure cycle for ease of separation from the molds and to prevent costly breakage of molds at separation. This early removal, however, requires post-curing of the cast lenses wherein exposure to oxygen normally inhibits further polymerization of the surfaces of the lenses. Accordingly, the lenses are left vulnerable to surface abrasion and are difficult to dye to uniform color densities.
In view of the foregoing, an object of this invention is to avoid the usual low surface cure of post-cured lenses that have been removed from their molds early in the preliminary curing cycle.
A further object is to accomplish greater than usual yield and quality of cast lens products with minimal cost and complication of equipment and/or procedure.
Other objects and advantages of the invention will become apparent from the following description.